This invention relates to new substituted 4-(2,4-diaminophenoxymethyl)-1,3-dioxolanes corresponding to general formula (I): ##STR2## to processes for their production and to their use as hair colorants.
So-called oxidation dyes are used for coloring keratin fibers because they ultimately provide extremely fast intensive colors. Under boundary in-use conditions (low coloring temperature, short coloring time), they give fast, intensive colors. The actual dyes are formed by the oxidative coupling of a primary intermediate and a secondary intermediate during the coloring process. Numerous primary and secondary intermediates for obtaining various color tones, hereinafter referred to as hair dye intermediates, are described in the literature (K. Venkataraman, The Chemistry of Synthetic Dyes, Vol. V, Academic Press, 1971; F. Brody and M. S. Burns, J. Soc. Cosmet. Chem. 19, 361-379, 1968; H. Husemeyer, J. Soc. Cosmet. Chem. 25, 131-138, 1974).
Although in principle the oxidative coupling reaction, i.e. development of the color, can be carried out with atmospheric oxygen, it is generally too slow and/or provides uneven coloring results, so that chemical oxidizing agents are normally used. Preferred oxidizing agents are based on hydrogen peroxide and, besides hydrogen peroxide itself, on addition compounds thereof with urea, melamine or alkali metal perborate.
The use of 1-alkoxysubstituted 2,4-diaminobenzene derivatives as secondary intermediates is well known from the literature. Thus, DE-PS 38 06 237 and DE-OS 32 44 517 describe substituted 2,4-diaminoanisoles while DE-OS 27 37 138 describes substituted .beta.-hydroxy-2,4-diaminophenetols. The colors described therein produced an intensive blue color tone, but with a distinct red component which is visible in particular in lighter shades. Where it is desired to obtain natural shades combining adequate depth of color with an adequate grey-masking effect, the red component is a disadvantage. Accordingly, there was an urgent need to develop new secondary intermediates which would give intensive colors in the clear blue range. It has now surprisingly been found that the compounds of general formula (I) described in the present invention satisfy this requirement particularly effectively.